Convert odds to implied probability
Type a price and see the implied probability instantly. Then learn the part most punters miss: the price is not the true chance.
$4.00 implies a 25.0% chance — but that includes the bookmaker’s margin. It’s the price you’re offered, not the true chance.
Decimal
AU · NZ default
Fractional
UK · traditional · a/b
American
Moneyline · ±
Implied probability
includes margin
Edit any field — the other three recompute live. The implied % is the bookmaker’s probability: add up every runner in a market and it tops 100%. That excess is the overround, and it’s why this isn’t the true chance.
See real de-vigged fair odds on 60+ bookies
EVSTREAM strips the margin and shows the true price, live
One divide turns a price into a probability.
- ▸Shorter odds, higher implied chance. A $1.50 favourite implies a 66.7% chance; a $21.00 roughie implies just 4.8%.
- ▸It already bakes in the margin. Implied probability is the bookmaker’s number — padded so the book turns a profit. The real chance is lower than the price suggests.
- ▸Same maths, three dialects. Decimal, fractional and American odds are just different ways of writing one number.
Common odds, every format.
A cheat-sheet of the prices you’ll see most. Every value is computed by the same engine as the tool above.
| Decimal | Fractional | American | Implied % | “One in” |
|---|---|---|---|---|
| 1.20 | 1/5 | -500 | 83.3% | 1 in 1.2 |
| 1.50 | 1/2 | -200 | 66.7% | 1 in 1.5 |
| 1.91 | 10/11 | -110 | 52.4% | 1 in 1.9 |
| 2.00EVENS | 1/1 | +100 | 50.0% | 1 in 2 |
| 2.50 | 3/2 | +150 | 40.0% | 1 in 2.5 |
| 3.00 | 2/1 | +200 | 33.3% | 1 in 3 |
| 4.00 | 3/1 | +300 | 25.0% | 1 in 4 |
| 6.00 | 5/1 | +500 | 16.7% | 1 in 6 |
| 11.00 | 10/1 | +1000 | 9.1% | 1 in 11 |
| 21.00 | 20/1 | +2000 | 4.8% | 1 in 21 |
| 51.00 | 50/1 | +5000 | 2.0% | 1 in 51 |
Implied % includes the bookmaker’s margin — it is the price, not the true chance.
Odds & probability, answered.
What is implied probability?
Implied probability is the chance a price "suggests". Divide 100 by the decimal odds: a $4.00 price implies a 25% chance. It is the simplest way to read what a bookmaker is really saying about a runner.
Why don't the probabilities add up to 100%?
Add up the implied probability of every runner in a market and you'll get more than 100% — often 110–120%. That extra slice is the overround (the bookmaker's margin). It is how the book guarantees a profit, and it is baked into every price you see.
Is the implied probability the true chance?
No. Because the margin is built in, the true chance is always lower than the implied probability. To estimate the real number you have to remove the margin — "de-vigging" — which is exactly what EVSTREAM does across 60+ bookies in real time.
Decimal, fractional or American — which should I use?
In Australia and New Zealand, decimal is standard — your total return per $1 staked. Fractional is the old UK style (3/1), and American/moneyline (+300) is common in the US. They are identical underneath; use whichever you read fastest.
How do I convert decimal odds to American?
For odds of 2.00 or longer: (decimal − 1) × 100 → e.g. 4.00 becomes +300. For odds under 2.00: −100 ÷ (decimal − 1) → e.g. 1.50 becomes −200. The converter does it instantly, both ways.
Stop guessing the true price.
This tool reads the bookmaker’s number. EVSTREAM removes the margin and streams de-vigged fair odds across every bookie, every code — live.